1. Field of the Invention
The present invention relates to a system to support testing of electronic devices. More particularly, the present invention relates to a temperature control unit that can control the internal temperature of the chamber of a system to support the testing of electronic devices.
2. Description of the Related Art
A system to support the testing of electronic devices serves to provide electronic devices to a tester, so that they can be electrically contacted and tested by the tester. The system is also called a handler.
Electronic devices need to be tested in a state where they have been undergoing thermal stress. In this case, the system to support the testing of electronic devices provides a tester with electronic devices in a state where thermal stress is being applied to them, so that the tester tests them.
FIG. 1 is a plan view illustrating a general system to support the testing of electronic devices, which can apply thermal stress to electronic devices.
As shown in FIG. 1, the general system includes a loading device 110, a chamber 120, an unloading device 130, a temperature control unit 140, an inlet shutter 150, and an outlet part shutter 160.
The loading device 110 serves to load electronic devices on a carrier board CB located at a loading site LP.
The chamber 120 has an inlet 121 through which the carrier board CB is carried in and an outlet 122 through which the carrier board CB is carried out. It allows the electronic devices, loaded on the carrier board CB, to be assimilated with a test temperature condition and then to be tested through a tester.
The unloading device 130 sorts electronic devices loaded on the carrier board CB, according to the grade, and unloads them from the carrier board CB, where the carrier board CB is located at an unloading site UP after being carried out from the chamber 120 through the outlet 122.
The temperature control unit 140 controls the internal temperature of the chamber 120 to apply thermal stress to electronic devices located in the chamber 120. It is installed to the outside at the upper side of the chamber 120. It will be described in detail later.
The inlet shutter 150 and the outlet shutter 160 serve to open or close the inlet 121 and the outlet 122, so that the carrier board CB can be carried in to and carried out from the chamber 120 through the inlet 121 and the outlet 122, respectively. The inlet and outlet shutters 150 and 160 also serve to seal the chamber 120 and thus protect the inside of the chamber 120 from outside air. Technology regarding these inlet and outlet shutters 150 and 160 has been published through Korean Patent Publication NO. 10-2007-0063904 entitled “TEST HANDLER AND SHUTTER THEREFOR,” so their detailed description will be omitted in this application.
In FIG. 1, the trajectory indicated by symbol “C” shows a circulation path of the carrier board CB.
The temperature control unit 140, as shown in FIG. 2, includes a fan 141, a fan driving device 142, a fan housing 143, a heater 144, and a gas supplier 145.
The fan 141 serves to supply air to the chamber 120. The fan driving device 142 drives the fan 141.
The fan housing 143 includes the fan 141 therein. It has a suction hole 143a for sucking air from the chamber 120 and a discharging hole 143b for discharging it back into the chamber 120.
The heater 144 serves to heat air discharged through the discharging hole 143b. The gas supplier 145 supplies low temperature gas that can remove heat from the air.
The temperature control unit 140 sucks air from the chamber 120, transforms the state of the air to a desired state, and then discharges it into the chamber 120. As disclosed in Korean Patent Publication NO 10-2003-0029266 entitled “TEST HANDLER,” the temperature control unit 140 can be implemented in such a way to supply air to respective electronic devices in the chamber through ducts.
In order to efficiently maintain the temperature inside the chamber 120, the temperature control unit 140 sucks air from the chamber 120 and supplies it back to the chamber 120, as shown by arrows in FIG. 2. This process, however, makes it impossible to maintain a constant temperature inside the chamber 120, due to the heat from the electronic devices that are tested at room temperature testing. Consequently, the electronic devices cannot be properly tested at room temperature testing. Although heat from the electronic devices may be removed by low temperature gas, it is difficult to control the supply of low temperature gas to the chamber 120 in such a way as to maintain the internal temperature of the chamber 120. Although such a controlling operation is performed, it causes another problem in that resources (gas) must be wasted.
Furthermore, as described above, the inlet and outlet shutters 150 and 160 close the inlet 121 and the outlet 122 and seal the chamber 120 in order to maintain the internal temperature environment of the chamber 120 except when the carrier board CB is carried in and out. This process, however, causes the internal temperature of the chamber 120 to increase at room temperature testing, and this makes it difficult to test electronic devices at room temperature.